U.S. patent application number 10/698847 was filed with the patent office on 2005-08-18 for system and method for an ambient atmosphere ion thruster.
Invention is credited to Dressler, Gordon A..
Application Number | 20050178919 10/698847 |
Document ID | / |
Family ID | 34837666 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050178919 |
Kind Code |
A1 |
Dressler, Gordon A. |
August 18, 2005 |
System and method for an ambient atmosphere ion thruster
Abstract
A system and a method for an ambient atmosphere ion thruster
having a pair of permeable electrical members for accelerating
ambient atmosphere ions which enter the thruster due to a craft's
relative velocity. Neutral ambient atmosphere molecules in the
intake mass flux may also be ionized and subsequently accelerated
by the pair of permeable electrical members. Acceleration of any
entering mass comprises an exhaust mass flux which then produces a
net thrust. Such net thrust is then vectored by configuring and
orienting the thrusters for imparting axial and lateral
accelerations as well as pitch, yaw, and roll controls. The present
invention is operational in proximity to any celestial body having
a sensible atmosphere during a portion of the free trajectory or
during orbiting at altitude. Useful net thrust is thereby produced
without need for carrying reaction mass onboard a spacecraft.
Inventors: |
Dressler, Gordon A.;
(Manhattan Beach, CA) |
Correspondence
Address: |
LaRiviere, Grubman & Payne, LLP
P.O. Box 3140
Monterey
CA
93942
US
|
Family ID: |
34837666 |
Appl. No.: |
10/698847 |
Filed: |
October 30, 2003 |
Current U.S.
Class: |
244/171.1 |
Current CPC
Class: |
F03H 1/0012 20130101;
B64G 1/405 20130101 |
Class at
Publication: |
244/171.1 |
International
Class: |
B64G 001/40 |
Claims
What is claimed:
1. An ambient atmosphere ion thruster system, comprising at least
one ambient atmosphere ion thruster, the at least one ambient
atmosphere ion thruster comprising at least one pair of permeable
electrical members, the at least one pair of permeable electrical
members comprising a forward permeable electrical member and an aft
permeable electrical member, and the forward permeable electrical
member and the aft permeable electrical member, each having an
opposing polarity in relation to one another, for accelerating a
plurality of intercepted ambient atmosphere ions, the at least one
ambient atmosphere ion thruster being mounted to a craft, and at
least one reaction force being imparted to the craft by
accelerating the plurality of intercepted ambient atmosphere
ions.
2. A system, as recited in claim 1, further comprising at least one
insulating support structure for mechanically connecting the at
least one ambient atmosphere ion thruster to the craft, the at
least one insulating support structure having at least one
electrical feed for electrically connecting the at least one pair
of permeable electrical members to an electrical power source.
3. A system, as recited in claim 1, wherein each member of the at
least one pair of permeable electrical members is mechanically
connected to one another, wherein a plurality of ambient atmosphere
constituents, being intercepted by the at least one pair of
permeable electrical members, comprises an intake mass flux, and
wherein a plurality of accelerated ambient atmosphere ions,
imparting the reaction force to the craft, comprises an exhaust
mass flux.
4. A system, as recited in claim 1, wherein two ambient atmosphere
ion thrusters are fixedly mounted to opposing sides of the craft to
each orient an electric field for cooperatively boosting,
deboosting, and attitude-controlling the craft along a single
axis.
5. A system, as recited in claim 1, wherein four ambient atmosphere
ion thrusters are fixedly mounted to opposing vertices of the craft
to each orient an electric field for cooperatively boosting,
deboosting, and attitude-controlling the craft along two axes.
6. A system, as recited in claim 1, wherein two ambient atmosphere
ion thrusters are rotatably mounted to opposing sides of the craft
to each orient an electric field for cooperatively boosting,
deboosting, and attitude-controlling the craft along two axes as
well as for laterally thrusting the craft.
7. A system, as recited in claim 1, wherein four ambient atmosphere
ion thrusters are rotatably mounted to a set of locations selected
from a group consisting essentially of generally opposing vertices
of the craft and generally opposing surfaces of the craft to each
orient an electric field for cooperatively boosting, deboosting,
and attitude-controlling the craft along three axes as well as for
laterally thrusting the craft.
8. A system, as recited in claim 1, wherein a single annular
ambient atmosphere ion thruster is fixedly mounted to the craft to
orient an electric field for boosting and deboosting the craft.
9. A system, as recited in claim 1, wherein four ambient atmosphere
ion thrusters are fixedly mounted to a set of locations selected
from a group consisting essentially of generally opposing vertices
of the craft and generally opposing surfaces of the craft, and
wherein one opposing pair of the four thrusters is fixedly mounted
to the craft in a plane perpendicular to that of the remaining
opposing pair of thrusters to each orient an electric field for
cooperatively boosting, deboosting, and attitude-controlling the
craft along two axes as well as for laterally thrusting the
craft.
10. A system, as recited in claim 1, further comprising at least
one means for reversing the polarity of the at least one pair of
permeable electrical members for reversing thrust.
11. A system, as recited in claim 1, wherein the at least one
ambient atmosphere ion thruster is operable in a path selected from
a group consisting essentially of an orbit proximal to any
celestial body having a sensible atmosphere and in a free
trajectory.
12. A system, as recited in claim 1, further comprising at least
one auxiliary ionizing device selected from a group consisting
essentially of an electron bombardment ionizer, a radio frequency
ionizer, a microwave ionizer, an extreme ultraviolet ionizer, a
flash lamp ionizer, and a magnetic field ionizer for ionizing any
un-ionized constituents in the ambient atmosphere.
13. A system, as recited in claim 1, further comprising at least
one electromagnetic field modifying device selected from a group
consisting essentially of a permanent magnet and an electromagnetic
field projector for modifying the electromagnetic field of the
plurality of ambient atmosphere ions.
14. A system, as recited in claim 12, further comprising at least
one electromagnetic field modifying device selected from a group
consisting essentially of a permanent magnet and an electromagnetic
field projector for modifying the electromagnetic field of the
plurality of ambient atmosphere ions.
15. A system, as recited in claim 1, wherein the at least one pair
of permeable electrical members comprises at least one electrical
component selected from a group consisting essentially of at least
one pair of electrical grids and at least one pair of porous
electromagnetic structures.
16. A system, as recited in claim 1, wherein the at least one
ambient atmosphere ion thruster operates in a low Earth orbit in a
range of approximately 200 km to approximately 1000 km.
17. A system, as recited in claim 1, wherein the at least one
ambient atmosphere ion thruster operates in a low Earth orbit in a
range of approximately 300 km to approximately 1000 km.
18. A system, as recited in claim 1, further comprising an electron
gun for neutralizing any net operational charge buildup on the
craft due to operation of the at least one thruster.
19. A system, as recited in claim 12, further comprising an
electron gun for neutralizing any net operational charge buildup on
the craft due to operation of the at least one thruster.
20. A system, as recited in claim 1, wherein the at least one
thruster is mounted to the craft in a disposition selected from a
group consisting essentially of outboard and inboard.
21. An ambient atmosphere ion thruster method, comprising providing
at least one ambient atmosphere ion thruster, the at least one
ambient atmosphere ion thruster providing step comprising providing
at least one pair of permeable electrical members, the at least one
pair of permeable electrical members providing step comprising
providing a forward permeable electrical member and providing an
aft permeable electrical member, and the forward permeable
electrical member providing step and the aft permeable electrical
member providing step together comprising providing each member,
having an opposing polarity in relation to one another, for
accelerating a plurality of intercepted ambient atmosphere ions,
the at least one ambient atmosphere ion thruster being mounted to a
craft, and at least one reaction force being imparted to the craft
by accelerating the plurality of intercepted ambient atmosphere
ions.
22. A method, as recited in claim 21, further comprising the step
of providing at least one insulating support structure for
mechanically connecting the at least one ambient atmosphere ion
thruster to the craft, the at least one insulating support
structure having at least one electrical feed for electrically
connecting the at least one pair of permeable electrical members to
an electrical power source.
23. A method, as recited in claim 21, wherein the step of providing
the at least one pair of permeable electrical members comprises
mechanically connecting each member of the at least one pair to one
another, wherein the step of providing the at least one pair of
permeable electrical members comprises providing a plurality of
ambient atmosphere constituents, being intercepted by the at least
one pair of permeable electrical members, comprising an intake mass
flux, and wherein the step of providing the at least one pair of
permeable electrical members comprises providing a plurality of
accelerated ambient atmosphere ions, imparting the reaction force
to the craft, comprising an exhaust mass flux.
24. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing two ambient atmosphere ion thrusters being fixedly
mounted to opposing sides of the craft to each orient an electric
field for cooperatively boosting, deboosting, and
attitude-controlling the craft along a single axis.
25. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing four ambient atmosphere ion thrusters being fixedly
mounted to opposing vertices of the craft to each orient an
electric field for cooperatively boosting, deboosting, and
attitude-controlling the craft along two axes.
26. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing two ambient atmosphere ion thrusters being rotatably
mounted to opposing sides of the craft to each orient an electric
field for cooperatively boosting, deboosting, and
attitude-controlling the craft along two axes as well as for
laterally thrusting the craft.
27. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing four ambient atmosphere ion thrusters being rotatably
mounted to a set of locations selected from a group consisting
essentially of generally opposing vertices of the craft and
generally opposing surfaces of the to each orient an electric field
for cooperatively boosting, deboosting, and attitude-controlling
the craft along three axes as well as for laterally thrusting the
craft.
28. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing a single annular ambient atmosphere ion thruster being
fixedly mounted to the craft to orient an electric field for
boosting and deboosting.
29. A method, as recited in claim 21, wherein the step of providing
the at least one ambient atmosphere ion thruster comprises
providing four ambient atmosphere ion thrusters being fixedly
mounted to a set of locations selected from a group consisting
essentially of generally opposing vertices of the craft and
generally opposing surfaces of the craft, and wherein the step of
providing the at least one ambient atmosphere ion thruster
comprises providing one opposing pair of the four thrusters being
fixedly mounted to the craft in a plane perpendicular to that of
the remaining opposing pair of thrusters to each orient an electric
field for cooperatively boosting, deboosting, and
attitude-controlling the craft along two axes as well as for
laterally thrusting the craft.
30. A method, as recited in claim 21, further comprising the step
of providing at least one means for reversing the polarity of the
at least one pair of permeable electrical members for reversing
thrust.
31. A method, as recited in claim 21, wherein the at least one
ambient atmosphere ion thruster providing step comprises operating
the at least one ambient atmosphere ion thruster in a path selected
from a group consisting essentially of an orbit proximal to any
celestial body having a sensible atmosphere and in a free
trajectory.
32. A method, as recited in claim 21, further comprising the step
of providing at least one auxiliary ionizing device selected from a
group consisting essentially of an electron bombardment ionizer, a
radio frequency ionizer, a microwave ionizer, an extreme
ultraviolet ionizer, a flash lamp ionizer, and a magnetic field
ionizer for ionizing any un-ionized constituents in the ambient
atmosphere.
33. A method, as recited in claim 21, further comprising the step
of providing at least one electromagnetic field modifying device
selected from a group consisting essentially of a permanent magnet
and an electromagnetic field projector for modifying the
electromagnetic field of the plurality of ambient atmosphere
ions.
34. A method, as recited in claim 32, further comprising the step
of providing at least one electromagnetic field modifying device
selected from a group consisting essentially of a permanent magnet
and an electromagnetic field projector for modifying the
electromagnetic field of the plurality of ambient atmosphere
ions.
35. A method, as recited in claim 21, wherein the step of providing
the at least one pair of permeable electrical members comprises
providing at least one electrical component selected from a group
consisting essentially of at least one pair of electrical grids and
at least one pair of porous electromagnetic structures.
36. A method, as recited in claim 21, wherein the at least one
ambient atmosphere ion thruster providing step comprises operating
the at least one ambient atmosphere ion thruster in a low Earth
orbit in a range of approximately 200 km to approximately 1000
km.
37. A method, as recited in claim 21, wherein the at least one
ambient atmosphere ion thruster providing step comprises operating
the at least one ambient atmosphere ion thruster in a low Earth
orbit in a range of approximately 300 km to approximately 1000
km.
38. A method, as recited in claim 21, further comprising the step
of providing an electron gun for neutralizing any net operational
charge buildup in the at least one thruster.
39. A method, as recited in claim 32, further comprising the step
of providing an electron gun for neutralizing any net operational
charge buildup in the at least one thruster.
40. A method, as recited in claim 21, wherein the at least one
thruster providing step comprises mounting the at least one
thruster to the craft in a disposition selected from a group
consisting essentially of outboard and inboard.
Description
TECHNICAL FIELD
[0001] The present invention relates to spacecraft dynamics and
spacecraft control systems and methods. More particularly, the
present invention relates to spacecraft propulsion and spacecraft
control systems and methods. Even more particularly, the present
invention relates to satellite propulsion and satellite control
systems and methods.
BACKGROUND ART
[0002] Rocket thrusting in space environments (e.g., at altitudes
greater than 200 km above Earth's surface) has presumed that a
propellant must be carried on board as a reaction mass (i.e., a
fuel source). Related art space vehicles are typically propelled by
carrying a reaction mass, chemically reacting or heating, or
applying kinetic energy to, the mass and subsequently expelling the
reacted mass, thereby propelling (i.e., thrusting) the space
vehicle. Such related art propulsion systems usually comprise a
fuel or reaction mass source and an energy source, which may be a
chemical source, a photovoltaic source, a nuclear source, and/or a
solar-thermal source.
[0003] Many spacecraft, specifically orbiting satellites operating
in the near-Earth space environment (herein defined only for the
purpose of discussion as being in the altitude range of 200 km to
1000 km above Earth's mean surface), require propulsion system
operation to either maintain or adjust the spacecraft's altitude,
the altitude and the velocity being affected by the presence of
drag from residual atmospheric constituents. For example, the
International Space Station ("ISS") currently requires frequent
propulsive reboosting that necessitates refueling with propellants.
Orbital decay, due to atmospheric drag, presents a major
life-limiting issue for satellites, especially for reconnaissance
and remote sensing satellites, which cannot be feasibly refueled to
replenish propellants expended during propulsive reboosting.
[0004] Further, a need exists for surveillance satellites to
maintain a lower Earth orbit in order to improve resolution of
optical imaging, radar imaging, and infrared imaging. Such lower
Earth orbit inherently involves greater atmospheric drag. The
related art counters atmospheric drag by either accepting the
situation and allowing for normal orbital decay before reentry
(i.e., a satellite design life of less than about five years) or by
carrying on-board propellant to maintain orbital altitude and to
thereby extend operating life. Other related art space propulsion
systems have employed gravitational gradients and geomagnetic
fields for attitude stabilization; however, these methods do not
provide the net thrust that is necessary for altitude control.
[0005] Yet other related art space propulsion systems have proposed
a "scooped" electric thruster in conjunction with a decreased
on-board propellant load (i.e., the "aero-assisted" orbital
transfer vehicle utilizing atmosphere ingestion, referring to prior
art FIG. 1). Such scooped electric thrusters comprise a "scoop" (a
large parabolic intake nozzle) 1 and an engine 2 having an inlet 3
for receiving the intake mass flow 4 and an outlet 5 for expelling
the exhaust mass flow 6 (prior art FIG. 1). The scoop is required
to compress the intake mass flow 4 and to direct it into the engine
where it would be electrically heated or ionized and
electromagnetically accelerated. Such scoops have been known to
impart considerable drag, because they decelerate the intake mass
flow 4. In order for such scoops to become operational, they must
be light, deployable, and power-conservative. Inflatable structures
and magnetic nozzles have been proposed to realize the development
of a working scoop. Significantly, the scoop art does not suggest
eliminating the scoop structure, eliminating the need for
compressing the intake mass flow 4, nor using an ambient gas
ionization level "as is" and without additional ionization of
ambient neutral species.
[0006] "Ionic breeze" air purifiers use electric devices for moving
ambient air; however, such devices are not known to have been
applied to space propulsion systems nor has their use been
suggested for use in the sparse atmosphere of the near-Earth space
environment. Toy devices, known as "lifters," use a tethered ion
breeze device for lifting a light frame from the ground. Lifters
have not been found to be practical for any significant
transportation purpose, because they require substantially high
voltage (e.g., >15 kV) for operation. Moreover, the ionic breeze
devices being implemented in air purifiers, as well as toy lifters,
rely on the relatively dense atmosphere found near Earth's surface;
and they have not been suggested nor demonstrated for operation in
the sparse atmosphere of the near-Earth space environment (i.e., in
the altitude range of at least 200 km above Earth's mean surface).
Although some recent experimental work has been performed using ion
breeze engines for endo-atmospheric ion propulsion, such work has
been shown to require a magneto-hydrodynamic slipstream
acceleration for hypersonic flight to at least orbital velocities
at the top of the atmosphere.
[0007] While photon reflection has been also used as a "mass-less"
method for providing thrust (e.g., solar sails and laser levitation
of particles), such thrust has been demonstrated as being extremely
low, and any thrust vectoring as being limited to a 180.degree. arc
centered on the vector of incident radiation.
[0008] Therefore, a long-felt need remains for a system and a
method which provide useful drag compensation, useful thrust,
useful torque, and useful attitude control for a space or an
aerospace vehicle, regardless of size, while eliminating the
expenditure of any reaction mass being carried on board the craft
for these purposes.
DISCLOSURE OF THE INVENTION
[0009] The present invention involves a system and a method for an
ambient atmosphere ion thruster ("AAIT") that provide useful drag
compensation, useful thrust, useful torque, and useful attitude
control for a spacecraft or an aerospace vehicle ("craft"),
regardless of size, while eliminating the expenditure of any
reaction mass being carried on board the craft for these purposes.
The present invention comprises at least one ambient atmosphere ion
thruster using only ambient atmospheric constituents (e.g., He,
N.sub.2, N.sup.+, O, and O.sup.+) for its reaction mass in the
near-Earth space environment, thereby necessitating only enough
electrical power consumption for orbit drag compensation
("make-up"), boosting/deboosting, orbit ephemeris maintenance,
and/or craft attitude and control. In essence, the present
invention comprises the electromagnetic acceleration of only
ambient atmosphere constituents for propulsion and attitude
control, with specific recognition that the fraction of
constituents naturally existing in an ionized state may be
sufficient for effecting the purpose of the present invention in
some cases. More specifically, the present invention does not
utilize any scoop device nor any other device for compressing the
intake mass flow (i.e., the incoming intercepted ambient atmosphere
gas flux).
[0010] The at least one ambient atmosphere ion thruster may
comprise at least one pair of permeable electrical members for
accelerating ambient atmosphere ions which enter the at least one
thruster due to the craft's relative velocity. Neutral ambient
atmosphere molecules may be further intercepted and ionized by the
present invention and then subsequently accelerated by the at least
one pair of permeable electrical members. Acceleration of any
entering mass comprises a mass flux which then produces a net
thrust. Such net thrust is then vectored by configuring and
orienting the present invention thruster(s), being mounted either
inboard or outboard the craft, for imparting axial and lateral
accelerations as well as pitch, yaw, and roll ("P/Y/R") torques to
the craft.
[0011] The two permeable electrical members (a forward member and a
complementary aft member) of each at least one pair of permeable
electrical members are separated by a distance and disposed at a
parallel or an approximately parallel orientation for intercepting
any ambient atmosphere ions, atoms, and molecules between the
forward member and the aft member from the vicinity of the craft.
The two members of each at least one pair of permeable electrical
members are electrically charged with respect to one another (i.e.,
one is positively charged while the other is negatively charged)
for accelerating the ions by the therebetween developed
electrostatic field. The at least one pair of permeable electrical
members may be mechanically connected by at least one electrically
insulating support structure to the craft. The at least one
electrically insulating support structure may have at least one
electrical feed. Each member of the at least one pair of permeable
electrical members comprises a high ratio of orifice area to
lattice area for maximizing the mass flux throughput. The craft
experiences a reactionary force from the accelerated ions, thereby
providing a significant net thrust and/or torque for propelling the
craft as well as for controlling the attitude of the craft.
[0012] The at least one pair of permeable electrical members and
any ancillary equipment may further comprise a configuration and a
voltage for ionizing uncharged particles (atoms or molecules)
intercepted between the members of each at least one pair of
permeable electrical members in order to supply reaction material
beyond that provided by the ion density of the medium through which
the craft is passing. The present invention also comprises an
electrical power source for charging the at least one pair of
permeable electrical members and for sustaining acceleration of the
ions as well as any further ionization of the intercepted mass
flux, wherein the electrical power source is provided for a
duration imparting a desired reactive thrust and/or torque. The
overall electrical circuitry and supporting ancillary equipment are
configured to avoid any excessive electrical charging of the craft
during operation by a technique such as using an electron gun for
neutralizing the ion flux exiting the aft permeable electrical
member of the at least one pair of permeable electrical members.
The present invention may further comprise a thrust reverser
achieved by reversing the relative polarity of each member of the
at least one pair of permeable electrical members. Reversing the
relative polarity of each member of the at least one pair of
permeable electrical members may comprise reversing the polarity of
the terminals of the electrical power source. Reversing the
polarity of the terminals of the electrical power source may
comprise mechanically actuating the electrical power source. The
present invention may further comprise at least one gimbal for the
at least one pair of permeable electrical members and the ancillary
equipment for further attitude control.
[0013] Advantages of the present invention include, but are not
limited to, significant performance, cost, reliability, and safety
benefits by reducing or eliminating on-board propellants and any
associated handling/support hardware and software from the craft,
development of more thrust per unit weight, development of thrust
in any direction with respect to the craft, operation in close
proximity to any celestial body having a sensible atmosphere (e.g.,
Mars, Venus, Jupiter, Saturn, and Europa), and operation in the
absence of sunlight. As such, new low Earth orbit ("LEO") missions
(i.e., orbits having an altitude in a range of less than
approximately 1000 km, geosynchronous transfer orbit ("GTO")
missions, and planetary missions) may be enabled by the present
invention. Many satellite missions, such as reconnaissance
missions, Earth resource mapping, space-based missile defense,
atmospheric research, and ionospheric research, may be improved by
maintaining a continuous lower Earth orbit which is provided by the
present invention.
[0014] Additional advantages may be obtained by employing at least
one AAIT on a craft for providing thrust and/or torque in any
desired direction. Such additional advantages include, but are not
limited to, alignment of thrust with the velocity vector
intersecting or nearly intersecting the craft center of mass for
providing a boost propulsive force, alignment of thrust opposing
the velocity vector and intersecting or nearly intersecting the
craft center of mass for providing a deboost propulsive force
(thrust reverser), alignment of thrust in a direction normal to the
velocity vector and intersecting or nearly intersecting the craft
center of mass for providing resolved force components effecting a
lateral thrust, and alignment of thrust in a direction of any of
the three principle axes without intersecting nor nearly
intersecting the craft center of mass for providing resolved force
components effecting a pitch torque, a yaw torque, and/or a roll
torque. Other features of the present invention are disclosed, or
are apparent in the section entitled "Detailed Description of the
Invention," disclosed, infra.
BRIEF DESCRIPTION OF THE DRAWING(S)
[0015] For a better understanding of the present invention,
reference is made to the below referenced accompanying Drawing(s).
Reference numbers refer to the same or equivalent parts of the
present invention throughout the several figures of the
Drawing(s).
[0016] FIG. 1 is a cross-sectional view of an aero-assisted orbital
transfer vehicle utilizing atmosphere ingestion comprising a scoop
(a parabolic intake "nozzle"); and an engine, in accordance with
the prior art.
[0017] FIG. 2 is a perspective view of at least one ambient
atmosphere ion thruster comprising at least one pair of permeable
electrical members, the at least one thruster being mounted to a
craft by at least one insulating support structure having at least
one electrical feed (conduit), and ambient atmosphere constituents
being intercepted by the at least one pair of permeable electrical
members comprising an intake mass flux, and a reaction force being
experienced by the craft from accelerated ions comprising an
exhaust mass flux, in accordance with a first embodiment of the
present invention.
[0018] FIG. 3 is a rear view taken along a velocity vector of two
ambient atmosphere ion thrusters, fixedly mounted to opposing sides
of a craft for boost, deboost, and attitude control along a single
axis, in accordance with a second embodiment of the present
invention, with typical craft appendages, such as a solar array or
radio frequency (RF) antenna being shown for reference only.
[0019] FIG. 4 is a rear view taken along a velocity vector of four
ambient atmosphere ion thrusters, fixedly mounted to opposing
vertices of a craft for boost, deboost, and attitude control along
two axes, in accordance with a third embodiment of the present
invention, with typical craft appendages, such as a solar array or
radio frequency (RF) antenna being shown for reference only.
[0020] FIG. 5 is a rear view taken along a velocity vector of two
ambient atmosphere ion thrusters, rotatably mounted to opposing
sides of a craft for boost, deboost, and attitude control along two
axes as well as for lateral thrust, in accordance with a fourth
embodiment of the present invention, with typical craft appendages,
such as a solar array or radio frequency (RF) antenna being shown
for reference only.
[0021] FIG. 6 is a rear view taken along a velocity vector of four
ambient atmosphere ion thrusters, rotatably mounted to opposing
vertices of a craft for boost, deboost, and attitude control along
three axes as well as for lateral thrust, in accordance with a
fifth embodiment of the present invention, with typical craft
appendages, such as a solar array or radio frequency (RF) antenna,
shown for reference only.
[0022] FIG. 7 is a rear view taken along a velocity vector of a
single annular ambient atmosphere ion thruster, fixedly mounted to
a craft for boost and deboost, in accordance with a sixth
embodiment of the present invention, with typical craft appendages,
such as a solar array or radio frequency (RF) antenna, shown for
reference only.
[0023] FIG. 8 is a rear view taken along a velocity vector of four
ambient atmosphere ion thrusters, fixedly mounted to opposing
vertices of a craft, wherein one opposing pair of thrusters is
fixedly mounted in a plane perpendicular to the remaining opposing
pair of thrusters, for boost, deboost, and attitude control along
two axes as well as for lateral thrust, in accordance with a
seventh embodiment of the present invention, with typical craft
appendages, such as a solar array or radio frequency (RF) antenna,
shown for reference only.
[0024] FIG. 9 is a graph of the nominal daylight composition, in
terms of particles per cubic centimeter, of Earth's upper
atmosphere, in terms of altitude, wherein variations of several
orders of magnitude in composition of the various noted species are
possible due to solar influences, the compositions and variations
being important with respect to the present invention.
[0025] FIG. 10 is a graph of the typical variations in certain
parameters, electron density and temperature, of Earth's upper
atmosphere, in terms of altitude, ranging from minimum solar
activity to maximum solar activity with respect to the present
invention.
[0026] FIG. 11 is an operational flowchart of an AAIT system,
further comprising subsystems such as at least one optional
auxiliary ionizing device selected from a group consisting
essentially of an electron bombardment ionizer, a radio frequency
ionizer, a microwave ionizer, an extreme ultraviolet ionizer, a
flash lamp ionizer, and a magnetic field ionizer for ionizing any
un-ionized constituents in the ambient atmosphere; at least one
optional electromagnetic field modifying device selected from a
group consisting essentially of an electron gun, a permanent
magnet, and an electromagnetic field projector for modifying the
electromagnetic field of the plurality of ambient atmosphere ions
and/or auxiliary ionized species; a power source; a power storage;
and power processing electronics, in accordance with the present
invention.
MODES FOR CARRYING OUT THE INVENTION
[0027] FIG. 2 illustrates, in a perspective view, the AAIT system
comprising at least one ambient atmosphere ion thruster 100
comprising at least one pair of permeable electrical members 10,
10', the at least one thruster 100 being mounted to a craft 1000 by
at least one insulating support structure 20, 20' having at least
one electrical feed (conduit) 30, 30', ambient atmosphere
constituents being intercepted by the at least one pair of
permeable electrical members 10, 10' and comprising an intake mass
flux 40, and a reaction force, thrust T, being experienced by the
craft 1000 from accelerated ions present within an exhaust mass
flux 50, in accordance with a first embodiment of the present
invention. The at least one pair of permeable electrical members
10, 10' may comprise at least one electrical component selected
from a group consisting essentially of at least one pair of
electrical grids and at least one pair of porous electromagnetic
structures. Each member of the at least one pair of permeable
electrical members 10, 10' may also be structurally connected, but
not electrically connected, to one another by the at least one
insulating support structure 21. The intake mass flux 40 may
comprise predominant constituents such as He, N.sub.2, N.sup.+, O,
and O.sup.+ for operation of the present invention in the
near-Earth space environment (also indicated in FIG. 9). While the
at least one ambient atmosphere ion thruster 100 of FIG. 2 is shown
in an outboard disposition, all possible inboard dispositions of
the at least one ambient atmosphere ion thruster 100 are also
hereby encompassed by the present invention.
[0028] Also in FIG. 2, the time derivatives of the intake mass
flux' 40 momentum of all species is represented by the product
expression m.sub.dot.times.v.sub.s/c, wherein m.sub.dot=the
intercepted mass flow rate and v.sub.s/c=velocity of the craft. The
time derivative of the exhaust mass flux' 50 momentum is
represented by the sum of the product expressions m.sub.dot
(ion).times.(v.sub.s/c+.DELTA.v.sub.ion
acc)+m.sub.dot(non-ion).times.v.sub.s/c=M.sub.dot
(ion).times.v'+M.sub.do- t(non-ion).times.v.sub.s/c, wherein
m.sub.dot(ion)=the accelerated ions mass flow rate and
m.sub.dot(non-ion)=the non-ionized mas flow rate,
v.sub.s/c=velocity of the craft, .DELTA.v.sub.ion acc=the change in
velocity of the accelerated ions, and v'=v.sub.s/c+.DELTA.v.sub.ion
acc. The net thrust T being produced is equal to the difference
between the time derivatives of the exhaust mass flux momentum and
the intake mass flux momentum, wherein
T=m.sub.dot(ion).times..DELTA.v.sub.ion acc, in accordance with a
first embodiment of the present invention. All naturally occurring
non-ionized atmospheric constituents within the intake mass flux 40
that are not further ionized in the present invention throughput or
by optional auxiliary equipment, such as auxiliary ionizers, will
not be accelerated and will then exit the electrical member 10'
with the same velocity, v.sub.s/c, as such existing non-ionized
atmospheric constituents already had upon entering the electrical
member 10, thereby not contributing to the net thrust. Such
"natural" mass flux may have an insignificant momentum exchange
with the accelerated ions, due to their low density; however, they
will still contribute some significant additional drag force as
they impact the permeable electrical members 10, 10'.
[0029] Also referring to FIG. 2 and by example only, the present
invention, as sized for a 1-m.sup.2 electrical member operating at
500 V with a 0.2-m electrical member spacing at an altitude of 400
km above Earth's mean surface, may provide a thrust T in a range of
approximately 2.0.times.10.sup.-6 N to approximately
2.0.times.10.sup.-4 N, wherein T=d/dt
(m.times.v)=m.sub.dot(ion).times..DELTA.v.sub.ion acc. Thus, for
T=2.0.times.10.sup.-6 N, wherein m.sub.dot(ion)=2.6.times.10.sup.-8
g/s (O.sup.+) to 8.9.times.10.sup.-10 g/s (N.sup.+), then
.DELTA.v.sub.ion acc=78 km/s (O.sup.+) to 83 km/s (N.sup.+) based
on no additional ionization; and for T=2.0.times.10.sup.-4 N, and
wherein m.sub.dot (ion)=2.9.times.10.sup.-6 g/s, then
.DELTA.v.sub.ion acc=59 km/s (N.sub.2.sup.+) to 155 km/s (He.sup.+)
based on full auxiliary ionization of all incoming species,
recognizing that relatively lighter ions, such as (He.sup.+), are
more rapidly accelerated than relatively heavier ions, such as
N.sub.2.sup.+, in any given electric field.
[0030] The present invention may further comprise a thrust reverser
100' (not shown) achieved by reversing the relative polarity of
each member of the at least one pair of permeable electrical
members 10, 10'. In this manner, the ions in the intake mass flux
40 are decelerated instead of being accelerated, thereby providing
a net thrust T' (not shown) in a direction opposite to the original
thrust T direction (FIG. 2). Reversing the relative polarity of
each member of the at least one pair of permeable electrical
members 10, 10' may comprise reversing the polarity of the
terminals of at least one power source 90 (shown in FIG. 11).
Reversing the polarity of the terminals of the at least one power
source 90 may also comprise mechanically actuating the at least one
power source 90. The present invention may further comprise at
least one gimbal (not shown) for the at least one pair of permeable
electrical members 10, 10' and the typical craft appendage 60
(shown in FIG. 11) for further attitude control.
[0031] FIG. 3 illustrates, in a perspective view, a rear view taken
along a velocity vector of two ambient atmosphere ion thrusters
100, fixedly mounted to opposing sides of a craft 1000 to orient an
electric field for boosting, deboosting, and attitude-controlling
the craft 1000 along a single axis, with typical craft appendages
60, such as a solar array or radio frequency (RF) antenna shown for
reference only, the two thrusters 100 being mounted to the craft
1000 by at least one insulating support structure 20, 20' having at
least one electrical feed (conduit) 30, 30', in accordance with a
second embodiment of the present invention. While the two ambient
atmosphere ion thrusters 100 of FIG. 3 are shown in an outboard
disposition, all possible inboard dispositions of the two ambient
atmosphere ion thrusters 100 are also hereby encompassed by the
present invention.
[0032] FIG. 4 illustrates, in a perspective view, a rear view taken
along a velocity vector of four ambient atmosphere ion thrusters
100, fixedly mounted to opposing vertices of a craft 1000 to each
orient an electric field for cooperatively boosting, deboosting,
and attitude-controlling the craft 1000 along two axes, with
typical craft appendages 60, such as a solar array or radio
frequency (RF) antenna shown for reference only, the four thrusters
100 being mounted to the craft 1000 by at least one insulating
support structure 20, 20' having at least one electrical feed
(conduit) 30,30', in accordance with a third embodiment of the
present invention. While the four ambient atmosphere ion thrusters
100 of FIG. 4 are shown in an outboard disposition, all possible
inboard dispositions of the four ambient atmosphere ion thrusters
100 are also hereby encompassed by the present invention.
[0033] FIG. 5 illustrates, in a perspective view, a rear view taken
along a velocity vector of two ambient atmosphere ion thrusters
100, rotatably mounted to opposing sides of a craft 1000 to each
orient an electric field for cooperatively boosting, deboosting,
and attitude-controlling the craft 1000 along two axes as well as
for laterally thrusting the craft 1000, with typical craft
appendages 60, such as a solar array or radio frequency (RF)
antenna shown for reference only, the two thrusters 100 being
mounted to the craft 1000 by at least one insulating support
structure 20, 20' having at least one electrical feed (conduit) 30,
30', in accordance with a fourth embodiment of the present
invention. While the two ambient atmosphere ion thrusters 100 of
FIG. 5 are shown in an outboard disposition, all possible inboard
dispositions of the two ambient atmosphere ion thrusters 100 are
also hereby encompassed by the present invention.
[0034] FIG. 6 illustrates, in a perspective view, a rear view taken
along a velocity vector of four ambient atmosphere ion thrusters
100, rotatably mounted to opposing vertices of a craft 1000 to each
orient an electric field for cooperatively boosting, deboosting,
and attitude-controlling the craft 1000 along three axes as well as
for laterally thrusting the craft 1000, with typical craft
appendages 60, such as a solar array or radio frequency (RF)
antenna shown for reference only, the four thrusters 100 being
mounted to the craft 1000 by at least one insulating structure 20,
20' having at least one electrical feed (conduit) 30, 30', in
accordance with a fifth embodiment of the present invention. While
the four ambient atmosphere ion thrusters 100 of FIG. 6 are shown
in an outboard disposition, all possible inboard dispositions of
the four ambient atmosphere ion thrusters 100 are also hereby
encompassed by the present invention.
[0035] FIG. 7 illustrates, in a perspective view, a rear view taken
along a velocity vector of at least one annular ambient atmosphere
ion thruster 100, fixedly mounted to a craft 1000 to each orient an
electric field for cooperatively boosting and deboosting, with
typical craft appendages 60, such as a solar array or radio
frequency (RF) antenna, the at least one annular thruster 100 being
mounted to the craft 1000 by at least one insulating support
structure 20, 20' having at least one electrical feed (conduit) 30,
30', in accordance with a sixth embodiment of the present
invention. While the at least one annular ambient atmosphere ion
thruster 100 of FIG. 7 is shown in an outboard disposition, all
possible inboard dispositions of the at least one annular ambient
atmosphere ion thruster 100 are also hereby encompassed by the
present invention.
[0036] FIG. 8 illustrates, in a perspective view, a rear view taken
along a velocity vector of four ambient atmosphere ion thrusters
100, fixedly mounted to a set of locations selected from a group
consisting essentially of generally opposing vertices of a craft
and generally opposing surfaces of the craft, wherein one opposing
pair of thrusters 100 is fixedly mounted to the craft 1000 in a
plane perpendicular to the remaining opposing pair of thrusters 100
to each orient an electric field for cooperatively boosting,
deboosting, and attitude-controlling the craft 1000 along two axes
as well as for laterally thrusting the craft 1000, with typical
craft appendages 60, such as a solar array or radio frequency (RF)
antenna shown for reference only, the four thrusters 100 being
mounted to the craft 1000 by at least one insulating support
structure 20, 20' having at least one electrical feed (conduit) 30,
30', in accordance with a seventh embodiment of the present
invention. While the four ambient atmosphere ion thrusters 100 of
FIG. 8 are shown in an outboard disposition, all possible inboard
dispositions of the four ambient atmosphere ion thrusters 100 are
also hereby encompassed by the present invention.
[0037] FIG. 9 illustrates, in a graphical representation, the
nominal daylight composition, in terms of particle density
(particles/cm.sup.3) along the abscissa axis 101, of Earth's upper
atmosphere, in terms of altitude (km) along the ordinate axis 102,
wherein variations of several orders of magnitude in composition of
the various noted species are possible due to solar influences, the
compositions and variations being important with respect to the
present invention. FIG. 9 indicates the change in atmospheric
composition as a function of altitude (i.e., from rarefied gases,
primarily comprising 0 and N.sub.2, occurring at lower altitudes,
such as 250 km 103, to a mixture largely comprising positive ions
H.sup.+, O.sup.+, N.sup.+, and He.sup.+ as well as free electrons
106 at higher altitudes 104, such as 1000 km). The positive ion
composition, being influenced by ionizing radiation, typically
peaks 107 at approximately 250 km during daylight in a "quiet" sun
condition (i.e., a low solar storm, low sunspot number). At this
altitude range, the frictional forces incident upon a craft 1000,
such as a satellite, are substantial and are primarily caused by
the presence of neutral O and N.sub.2 species. The present
invention may be used to nearly continuously counteract such
frictional force (drag). While the composition of the upper
atmosphere is generally electrically neutral, the atmospheric mass
contains a minor level to a moderate level of positive ions which
are accelerated by the present invention. The electrons within the
intercepted mass flux, of course, are also accelerated in a
direction opposite to the positive ion acceleration vector (e.g.,
in the craft velocity vector direction for the case of AAIT
operation in a boost mode), thereby forming some counter-force,
albeit negligible due to the substantially lower electron mass
relative to any ion mass. Ionizing and consequently accelerating
previously neutral atoms or molecules may be desirable at the lower
altitude ranges, which is achieved by forming a photon or
electromagnetic field of a magnitude sufficiently great to effect
the ionization during the interception period of the ambient gas.
Preferably, the altitude for operating the present invention under
typical atmospheric conditions comprises a range of approximately
200 km to approximately 1000 km in LEO.
[0038] However, the preferable altitude range would vary as a
function of the celestial body around which the craft would operate
due to differences in atmospheric compositions, especially
differences in ion concentrations relative to neutral species. For
example, Mars, Venus, Jupiter, Saturn, and Europa are some of the
celestial bodies within the solar system which are known to have
sensible atmospheres. The present invention specifically involves
operation without limitation as to the relative chemical
composition of a given celestial body's atmosphere as long as the
particle number density falls within a wide range of possible
values. The present invention may also comprise using both the
pre-existing ionized species and the further ionized species, such
as the double-ionization of methane (CH.sub.4). The present
invention may also comprise using a naturally occurring heavy
atomic species such as xenon (Xe) for increasing the reactive
force.
[0039] FIG. 10 illustrates, in a graphical representation, the
typical variations in certain parameters, particle (especially
electron) density (particles/cm.sup.3) 201 and temperature (K) 202
along the abscissa axis, of Earth's upper atmosphere, in terms of
altitude (km) along the ordinate axis 203, ranging from minimum
solar activity 204, 205 to maximum solar activity 206, 207, which
is relevant to the present invention. Particle (electron) density
is a consideration for operating the present invention since the
atmosphere is generally electrically neutral and, as such,
indicates the corresponding availability of positive ions. The
thermal velocity of the ambient atmosphere constituents in the
foregoing altitude range comprises a significant fraction of the
orbital velocity, which is in a range of approximately 7.5 km/sec
to approximately 7.7 km/sec, of a craft 1000, such as a satellite,
in a near-circular orbit in the same altitude range. The particle
densities (shown in FIG. 9) indicate that the ambient atmosphere
flow, which is experienced by a craft 1000 in this altitude range,
is in the free molecular flow regime. Returning to FIG. 2, in free
molecular flow, the velocity of all naturally occurring ions is not
be limited to a direction being strictly normal to any at least one
pair of permeable electrical members 10, 10', but rather has
thermally-induced velocity components in random directions
superimposed on the relative flow direction which is opposite to
that of v.sub.s/c. As such, any at least one pair of permeable
electrical members 10, 10' oriented even in a plane along a
velocity vector will still intercept some ambient atmosphere
constituents.
[0040] FIG. 11 illustrates, in a schematic view, an operational
flowchart of an AAIT system, further comprising subsystems such as
at least one auxiliary ionizing device 11 selected from a group
consisting essentially of a synchrotron, an electron bombardment
ionizer, a radio frequency ionizer, an x-ray ionizer, a microwave
ionizer, an extreme ultraviolet (EUV) ionizer, a flash lamp
ionizer, and a magnetic field ionizer for ionizing any un-ionized
constituents in the ambient atmosphere and for ionizing double,
triple, or higher-order ionization levels of already-ionized
species, in accordance with the present invention. The present
system may also further comprise at least one electromagnetic field
modifying device selected from a group consisting essentially of an
electron gun 13 for dissipating any charge acquired by the craft
1000, a permanent magnet 12 for modifying the electromagnetic field
of the plurality of ambient atmosphere ions, and an electromagnetic
field projector 14 for modifying the electromagnetic field of the
plurality of ambient atmosphere ions, the at least one
electromagnetic field modifying device being incorporated into the
AAIT system for improving overall efficiency, for reducing wear,
for reducing generated electromagnetic interference, and for
otherwise providing proper operation of the system with respect to
an operating craft.
[0041] The AAIT system may comprise a power source 90, fed by at
least one ancillary equipment 61 comprising at least one power feed
equipment selected from a group consisting essentially of solar
cell array, a solar-thermal cell, solar-thermal collection
generator (including, but not limited to, a Rankine power cycle, a
Brayton power cycle, or a Sterling power cycle), a nuclear reactor,
a laser collector, a microwave collector, and the like; a power
storage 91, such as a battery, a rechargeable battery, a flywheel,
a fusible salt, and the like; and power processing electronics 92,
such as command interface electronics 92a (manual or automatic) and
state-of-health instrumentation and telemetry 92b. While the at
least one power feed equipment is illustrated as a solar cell, by
example only, any source of electrical power is acceptable. The
power source 90 may be "increment," in the case of solar power, or
may be "received energy," necessitating the addition of the power
storage device 91 during periods when the power source 90 is in the
off-mode. The switching and power processing may be accomplished by
the power processing electronics 92 which are controlled by either
the manual or automatic command interface electronics 92a. The
power processing electronics 92 further receive information from
the state-of-health instrumentation and telemetry 92b. Power from
the power processing electronics 92 is conveyed to the at least one
pair of permeable electrical members 10, 10'. If desired, the ion
flow may be shaped and formed by the at least one electromagnetic
field modifying device (e.g., the permanent magnet 12 and the
electromagnetic field projector 14). Finally, the at least one
auxiliary ionizing device 11 may be disposed upstream of the
forward permeable electric member 10 for ionizing incoming neutral
particles. The at least one auxiliary ionizing device 11 may use
EUV, RF, x-ray, or any other electromagnetic radiation for ionizing
the neutral particles.
[0042] The present invention may be applicable to uses such as
providing continuous drag make-up thrusting for large scale craft
such as the ISS operating in an LEO environment. Assuming daylight
and quiet sun conditions at 400 km, 10% overall power conversion
efficiency, 500 V with a 0.2-m spacing between the permeable
electrical members 10, 10', and full ionization of ambient
atmosphere species, the each at least one permeable electrical
member may comprise, by example only, a permeable area of
approximately 270 m.sup.2 with approximately 30 m.sup.2 additional
drag area which provides for operation at a 15% duty cycle (21.6 kW
for the AAIT being in the "on" mode; 3.3 kW being the average load)
or a permeable area of approximately 40 m.sup.2 with approximately
4 m.sup.2 additional drag area which provides for continuous
operation (3.0 kW being the average load) for drag compensation.
Assuming daylight and quiet sun conditions at 400 km, 10% overall
power conversion efficiency, 500 V per 0.2 m, and no additional
ionization of ambient atmosphere species, the each at least one
permeable electrical member may comprise, by example only, a
permeable area of approximately 4000/m.sup.2 with approximately 30
m.sup.2 additional drag area which provides for continuous
operation (3.0 kW being the average load) for drag
compensation.
[0043] Information as herein shown and described in detail is fully
capable of attaining the above-described object of the invention,
the presently preferred embodiment of the invention, and is, thus,
representative of the subject matter which is broadly contemplated
by the present invention. The scope of the present invention fully
encompasses other embodiments which may become obvious to those
skilled in the art, and is to be limited, accordingly, by nothing
other than the appended claims, wherein reference to an element in
the singular is not intended to mean "one and only one" unless
explicitly so stated, but rather "one or more." All structural and
functional equivalents to the elements of the above-described
preferred embodiment and additional embodiments that are known to
those of ordinary skill in the art are hereby expressly
incorporated by reference and are intended to be encompassed by the
present claims.
[0044] Moreover, no requirement exists for a device or method to
address each and every problem sought to be resolved by the present
invention, for such to be encompassed by the present claims.
Furthermore, no element, component, or method step in the present
disclosure is intended to be dedicated to the public regardless of
whether the element, component, or method step is explicitly
recited in the claims. However, various changes and modifications
in form, thruster material, and fabrication material detail that
may be made without departing from the spirit and scope of the
inventions as set forth in the appended claims should be readily
apparent to those of ordinary skill in the art. No claim herein is
to be construed under the provisions of 35 U.S.C. .sctn. 112, sixth
paragraph, unless the element is expressly recited using the phrase
"means for."
INDUSTRIAL APPLICABILITY
[0045] The present invention applies industrially to propulsion
systems employing AAITs which include, but are not limited to, the
following operations during those portions of orbital or free
trajectory flight passing through the sensible atmosphere
associated with any celestial body: drag compensation for a craft
in LEO (e.g., in an altitude range of approximately 200 km to
approximately 1000 km), and for craft orbiting other celestial
bodies, thereby permitting continuous operation of the craft at low
altitudes otherwise requiring either more or less continuous
expenditure of on-board propellant; boost from a low altitude,
near-circular orbit to an elliptical orbit having an extremely
large apoapsis (e.g., apogee), even an apoapsis approaching an
escape trajectory; deboost from a high energy approach trajectory
or a high apoapsis elliptical orbit to a lower energy orbit, even
an orbit approaching the limit of aerodynamic stability or the
limit of permissible thermal heating; deboost/boost in a sequence
that permits "atmospheric dipping" having an orbit periapsis (e.g.,
perigee) at an otherwise unstable altitude; deboost for providing a
controlled terminal entry into the atmosphere; craft attitude
control about at least one principle axis (i.e., pitch, yaw, and/or
roll control); and orbital ephemeris maintenance (e.g.,
inclination, longitude of ascending node, semi-major axis,
eccentricity, etc.).
* * * * *